Control. Whether guns or money, food or medicine, it's always about control

Then again, it's better than the proposal of Peter Bofinger of the German Council of Economic Experts. He wants to abolish the use of cash, which he calls an anachronism. He frets that old-fashioned notes enable undeclared work and black markets, and stand in the way of central bank monetary policy. So rather than adjust policy to be more palatable to the public, he'd rather leave no shadows in which the public can hide from his preferred policies. The idea is to make all economic activity visible so that people have to submit to control.

Denmark, which has the highest tax rates in Europe and a correspondingly booming shadow economy, is already moving in that direction. With almost half the workforce in construction and agriculture laboring, at least sometimes, off the books, the Danmarks Nationalbank will stop internal printing of banknotes and minting of coins in 2016.

After all, why adjust tax and regulatory policy to be acceptable to constitutents when you can nag them and try to reinvent the idea of money instead?
And if you can only use a bank card, they they also have a record of everything you buy. 
And if you think that's just coincidental...